Q&A: Sealing Fire-Stop Penetrations

Sealing Fire-Stop Penetrations

Q.When we build
homes, we drill numerous holes through wall plates and
subfloor assemblies for wiring, plumbing, and hvac
ducts. Are there any code requirements for sealing the
gaps around these penetrations?

A.Redwood Kardon
responds: The model codes are clear about
sealing pipe and cable penetrations through draft
stops or fire-rated assemblies. The two codes I am
familiar with, theUniform Building
Code(1994 UBC, sections 708 &
709) and CABO’s One and Two Family
Dwelling Code (section 602.7), state that
fire-rated assemblies must be sealed with a
noncombustible material. One such material is
Flame-X (Firestops Systems, 12187 Industrial Rd.,
Surrey, BC V3V 3S1, Canada; 604/580-1788), a
gunnable one-component sealant that meets code
requirements.

This provision is intended to prevent
fire-carrying drafts from communicating between
floors, under stairs, or through large concealed
spaces. In practice, however, many jurisdictions do
not enforce this regulation when the wall cavities
are sufficiently insulated to retard drafts between
fire stops ( UBC , section 708.3.1) or
fire-rated assemblies ( UBC , Table
7-B).

In many areas, local energy efficiency
requirements stipulate that conditioned spaces be
sealed from nonconditioned spaces. Standard sealant
can be used if the penetrations are not located
within a fire stop or a fire-rated assembly.

Redwood Kardon is a building
inspector for the City of Oakland, Calif., and
author of Code Check , a field guide to
building a safe home. An online version of
Code Check can be found on the Web at
www.codecheck.com.